Ask the Expert: Mosquitoes, Termites and Millipedes


September 3, 2015

Q. A homeowner has mosquito problems in two bathrooms and a laundry room, which abut one another on a slab. The lawn outside is usually wet and soggy. I don’t believe the mosquitoes are entering from outside, but I can’t find other entry points. Any suggestions? — GARY C., FLORIDA

A. There might be a water problem beneath the slab. Drill a hole through the slab in an inconspicuous spot, then push a dowel down through the hole. If it comes back wet, the breeding problem might be beneath the slab. Leave the hole open, and cover it with a clear plastic cup to see whether mosquitoes emerge. If they do, one solution might be to introduce a larvicide through the hole to stop breeding. The other option is to solve the water problem — perhaps an irrigation line is leaking, for example.

Q. I inspected a house with a termite infestation. There’s a full basement with walls made of poured concrete. However, the foundation ends below grade, so a 3-ft. knee wall was constructed atop it to raise the first-floor living area. There’s a lot of wood-to-soil contact, and the termites are enjoying it. Should the wood be replaced with pressure-treated wood? What type of soil treatment should I provide? — JOHN B., NEW YORK

A. I wouldn’t touch that situation with a 10-ft. pole. If you do treat, I wouldn’t offer any guarantees. The ultimate solution would be to lower the grade (or raise the foundation) so there’s no wood-soil contact. Then the soil treatment or a bait system of your choice can be employed. If the entire lot can’t be regraded for practical reasons, a gutter of concrete and crushed stone can be placed against the foundation after a 1-ft.-wide trench is dug, to lower the soil against the foundation. Pressure-treated wood alone isn’t the answer.

Q. I’m treating for millipedes and have read it could take multiple applications to control them. The source seems to be thick mulch beds. Which insecticide should I use, and how should it be applied? I’ve been spraying the mulch unsuccessfully. — BRUCE O., ILLINOIS

A. Millipedes typically breed in the interface of soil and mulch. If you just spray the surface of the mulch, the insecticide probably isn’t moving down further than a quarter of an inch. Rod the mulch to reach the soil surface beneath, or rake it out. Then treat the soil and the bottom of the mulch, and push it back into place. Any fast-acting residual will work. Pyrethroids are particularly good on millipedes.

Q. In a recent column, you explained termite swarmers can’t fly but are carried by moving air. This is contrary to my experience. I’ve seen many swarming termites flying inside and outside, especially during calm days. Can you elaborate on your statement? — FRANK I., MASSACHUSETTS

A. You have a sharp eye. Termite swarmers can fly, but they don’t fly long distances because their wings break off at the normal break points. However, if swarming occurs outdoors and there is a breeze, the wind can carry swarmers some distance, which is how some colonies become established. Sorry for the confusion. 

Email your questions about insect identification and pest management technologies and techniques to Dr. Doug Mampe, an industry consultant, at Your questions most likely will be printed and answered in one of Pest Management Professional’s upcoming Ask the Expert columns.

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